About halfway through Nathalia Holt's book "Rise of the Rocket Girls" comes riveting stories about 1960s-era women fighting between the need to take time off to care for their new babies, and the desire to keep working at the Jet Propulsion Laboratory to help NASA begin its exploration of space.

One was told that pregnant women can't be around for "insurance reasons" and was fired on the spot (she was later rehired). Another made the decision to come back to work only seven weeks after giving birth; luckily, her mother lived close by and was able to take care of the young boy.

In an era with little maternity leave and where a small minority (only 25 percent) of women with young children were working, the women profiled in "Rocket Girls" turned out not only to be trailblazers for the solar system. They also were pioneers for the more accepting climate of women in sciences today, although many still say there is progress to be made.

"The institutional policies of JPL (NASA's Jet Propulsion Laboratory) are very key," Holt told Discovery News. Women working at JPL in the 1960s were mostly in the field of "computers", which referred to the staff that planned spacecraft trajectories and other complicated maneuvers.

"It was not about working 9 to 5 at a desk; it was about getting the work done. They were able to come in early when they need to. Leave early and pick up their children. They made their hours work with their lives."

Holt, who is new to writing about space exploration, first came across her topic when she was pregnant herself in 2010. She and her husband decided on the name "Eleanor Francis" and Googled the name to "make sure she wasn't a serial killer or something."

Holt instead found the profile of Eleanor Francis Helin, an American astronomer who discovered or co-discovered nearly 900 asteroids, and several comets besides. Helin worked at JPL and the California Institute of Technology for more than 30 years.

Holt said it was "very surprising to find this group of women, and so little is known about them." Archival photographs from JPL would show these women sitting at desks, with no captions showing who was who, Holt said. Holt began tracking down all the computers she could, and said she was lucky that many were still alive, and that the group was close-knit. Helin, sadly, had died a year before Holt initiated her search.

The pages of Holt's book are full of familiar milestones to people who read about space exploration. You'll see the names of Yuri Gagarin (the first man in space) and the Mercury astronauts, who kick-started American human space exploration. Also present is a mini-history of the first American space probes that explored the solar system, from the Ranger series that saw the moon, to the Mariner group that explored Mars, Venus and Mercury, the Voyager spacecraft that went out to the outer solar system, and even the space shuttle program that began flying in the 1980s.

But what is less explored in the literature - and highlighted in Holt's book - are the personal sacrifices JPL employees made to help NASA explore the solar system. (Few other accounts talk about shuttling children and the shame of divorce, for example.) It also talks about the contributions of women to the most recognized missions, such as Apollo 11. Even one of its most fundamental accomplishments - using a multi-stage rocket to get to the moon - was rooted in women's work, specifically the computations for the Bumper WAC (the first two-stage rocket in the world.)

Holt especially credits Barbara Paulson, a woman highlighted strongly in official NASA accounts of "computers", for helping her start the research. While Holt failed 11 times to find Paulson, the 12th proved to be the charm; "Without her sharp memory, quick wit and friendly attitude, I would have never been able to write this book," she said. The book reveals much about the family sacrifices of these women as they helped NASA reach the stars, as well as their lasting contributions for the females who continue occupying roles of all sorts - managerial and beginner - at JPL today.

The Apollo astronauts were so far from Earth that they could cover over the entire planet with their thumb. Fun fact: the crescent Earth (1/4 full) you see here hovering above the lunar module displays the opposite phase that the moon would have appeared to Earth at that time (3/4 full). Also, the Earth does not move

You can see here the Portable Life Support System (PLSS) that was used to keep astronauts alive on the surface by providing pressure, oxygen and water. The amount of cool air being sent to the astronaut could be changed at the flick of a switch, allowing astronauts to get a little air conditioning when they were moving around vehemently.

, which made it fairly useful for rocks and the equipment the astronauts needed to explore the surface. However, the rough lunar terrain sometimes made the wheels get stuck, forcing Mitchell and Shepard to occasionally carry it across the surface.

The Apollo 14 astronauts took a series of pictures showing how their lunar module, Antares, was positioned on the lunar soil. This let engineers back on Earth know how well the lunar module was performing, which would be crucial given that the LM was expected to carry a heavier load starting with Apollo 15 (the astronauts were staying longer and bringing a lunar buggy with them). Here you can see dust piling up around one of the legs of the LM. While the surface was powdery, the astronauts discovered that the regolith (lunar soil) packed down quickly a few inches below.

, it was intended in part to watch how the solar wind -- the constant stream of particles from the sun -- interacted with the moon as the moon orbited through Earth's magnetic field. SIDE experiments on the moon sometimes detected ions after micrometeroite impacts, which is believed to be gas released by the crash.

When astronauts head back to the moon, one of their primary concerns will be the dust. No matter how much they tried to brush off the powder when they came back inside the shelter of the LM, some still stuck. Then it tended to get

This is one of a series of shots that Stu Roosa, pilot of the command module, took of Antares flying away with his two crewmates inside. Roosa was expected to spend several days alone in the command module Orion, taking pictures of the moon and standing by in case his crewmates needed to make an emergency exit from the surface. Like most other command module pilots, Roosa said

Here is a view of the command module as Shepard and Mitchell made their way back from the lunar surface. The command module had undergone some redesigns following a near-fatal explosion on the Apollo 13 spacecraft that damaged the oxygen tank and other vital parts of the spacecraft, and Shepard said he had confidence in what NASA and contractors had done to fix the problem. "It gave us a little higher level of comfort with that extra training time," he said in